Fifty Shades of Grey

Sorry ladies ... Charlie Hunnam has just dropped out of the big screen adaptation of "Fifty Shades of Grey" -- and it's all because of his role on "Sons of Anarchy."

According to reports ... the decision was made because Hunnam wasn't able to "adequately prepare" for the role due to his "immersive" TV schedule.

Makes sense, since filming was supposed to begin on the movie later this month -- but just days ago Hunnam was talking up how seriously he had been taking the role ... so it's pretty surprising.

Melanie Griffith couldn't be happier for her daughter Dakota Johnson ... saying she's the "proudest mom ever" now that Dakota's playing a nymphomaniac sex slave in the "Fifty Shades of Grey" movie.

You'll recall, Griffith's daughter has just been cast in the role of Anastasia Steele, the protagonist in "Fifty Shades of Grey" alongside Charlie Hunnam (as Christian Grey).

If you know anything about the books, you'll know Anastasia becomes entwined in a disturbing and violent BDSM affair with Christian Grey, essentially becoming Christian's sex-addicted slave. You know, every mother's dream.

At least for Melanie ... watch the clip.

He ain't just into S&M, "Fifty Shades of Grey" star Charlie Hunnam is also into THC ... at least judging by the guy's wardrobe.

Hunnam was spotted at LAX wearing an Alternative Herbal Health Services shirt ... a popular marijuana dispensary in West Hollywood that has a marijuana vending machine and sells weed soda ... seriously.

Fun Fact -- Charlie once sparked a bowl for Snoop Lion during an Internet show (scroll to 11:38).

After months of middle-aged women speculating and debating who should bring "Fifty Shades of Grey" and its hard core sex scenes to life, we finally have the answer: Charlie Hunnam and Dakota Johnson.

Author E.L. James tweeted the news Monday -- the bondage/sex freak role of Christian Grey went to 33-year-old Hunnam -- best known for his role on "Sons of Anarchy".

23-year-old Dakota -- daughter of Melanie Griffith and Don Johnson -- will play Anastasia Steele, the college girl turned willing sex slave in the novel. Best known from Fox's cancelled comedy "Ben & Kate."

Ian Somerhalder, Colin Egglesfield, and Matt Bomer were at one time rumored frontrunners. Sorry guys.

Little advice for Charlie and Dakota: start stretching. Maybe invest in some ice packs.

"50 Shades of Grey" author E.L. James is a hack with no REAL sex experience ... at least according to porn legend Sasha Grey, who tells TMZ, she's way more qualified to write erotic fiction than some horny middle-aged woman.

In case you didn't know, 25-year-old Grey -- who starred in 271 adult films before officially retiring at age 23 -- just released her own erotic novel called The Juliette Society.

We asked Grey if she thinks she's more qualified to write erotica than 50-year-old former "Twilight" fanfic writer E.L. James ... and her response, "HELL YES."

She also tossed in a subtle insult, calling "50 Shades" a "romance" novel ... not real erotica.

Screw professional courtesy ... "Twilight" author Stephenie Meyer says she won't give E.L. James any casting advice for the upcoming "Fifty Shades of Grey" movie .. because she REFUSES TO READ THE BOOK!!!

Meyer was leaving Hemmingway's in Hollywood with some friends last night when she fired the shot ... and it ain't the first time she's taken aim at the S&M-heavy trilogy.

Earlier this year, Meyer told The Guardian "50 Shades" was "too smutty" for her taste -- explaining, "Erotica is not something I read. I don't even read traditional romance."

Forget carrying it in your purse -- now you can keep "Fifty Shades of Grey" where it matters most ... near your special lady place ... because TMZ has learned, the people behind the book just inked a massive women's underwear deal.

A rep for CopCorp Licensing tells TMZ, three apparel companies have just locked down the FIRST EVER licensing deals with author E.L. James to distribute "Fifty Shades"-themed clothes ... from t-shirts and hoodies ... to ladies' pantyhose, underwear, and pajamas.

According to CopCorp, FREEZE Clothing will be selling the knits, tees, and hoodies. A company called HYP will be selling hosiery, garters, and tights. And something called Briefly Stated will sell daywear, loungewear, and sleepwear (including underwear).

It's big news -- considering "Fifty Shades" is one of the most valuable licenses on the planet right now ... after the series sold more than 40 million copies worldwide.

The sultry bestseller "Fifty Shades of Grey" is causing a boom in the sex toy market -- in fact, a company that specializes in vaginal exercise balls says it's sold a record number of hoo-ha doodads in the last month ... all thanks to the book.

A rep for the sex toy company -- called Fun Factory -- just sent a thank you letter to "Fifty Shades" publisher Vintage Books, writing, "In the last month, our Smart Balls sales have gone up 300%."

In case you haven't read the book -- the main character Christian Grey uses a pair of Kegel exercise doohickeys called Ben-Wa balls on his female sex slave (for those with the book, skip to page 362).

The rep writes, "Thanks to the book, we are getting emails and calls from around the world asking about our Smart Balls ... Yesterday, the Fun Factory office received an email from a 74-year-old woman in Dubai who read the book while vacationing in the USA."